Knee Brace Composition - What Manual Tests Are Involved In Diagnosing An ACL Tear

The Lachman Test

Prior to ordering any tests, such as an MRI or an x-ray, a skilled examiner can often times detect an injury to your knee. One such manual test is the Lachman test. Named after John Lachman, M.D., the Lachman test is performed to test a person's ACL for stability. In specific, the goal of this particular test is to help determine if the ACL is torn, or intact.

To perform the Lachman test, the patient should be laying supine (on their back) with their knee in approximately 20-30 degrees of flexion. The leg that is being tested should also be externally rotated. The individual conducting the maneuver needs to place one hand on the patient's thigh, while the other hand needs to be placed behind the tibia, with one thumb placed on the tibial tuberosity. The examiner pulls anteriorly on the tibia to determine forward translation of the tibia on the femur. (The femur is the thigh bone, while the tibis is the larger of the two bones found in your leg.) When pulling anteriorly on the tibia, an intact ACL should prevent forward translation movement of the tibia on the femur. This is known as a "firm endpoint". On the other hand, if the end point is "soft", and the tibia can move forward on the femur, then this suggests that the ACL is torn.

The Anterior Drawer Test

A second commonly used test, among several, to determine the stability of the ACL is the Anterior Drawer Test. In this test, the patient is lying supine (on their back) with their hips flexed to 45 degrees and their knee to 90 degrees. The individual performing the test then grasps the tibia just below the knee, with their thumbs on either side of the patellar tendon. It is important to note that the hamstring muscle group must remain relaxed to help ensure a proper test. (The hamstrings can be tested using the index fingers of the examiner). The tibia is drawn forward, once the examiner is in position. An ACL injury can be evinced when the examiner notes that one limb has noticeably more anterior tibial translation in comparison to the opposing limb.

If these tests are positive and the ACL is sprained, or can be torn, a knee brace can help provide meaningful support and help reduce pain you may be experiencing. Knee braces are widely used among several sporting groups for individuals with previous ACL injuries. These brace can help provide the meaningful support to get them moving again with confidence.

Reference : Starkey, C., & Ryan, J. (2003). The Knee. Orthopedic & Athletic Injury Evaluation Handbook (pp.106). F.A. Davis Company